diff --git a/【实践课外】5.循环结构2/7-1 求整数段和.c b/【实践课外】5.循环结构2/7-1 求整数段和.c
new file mode 100644
index 0000000..222ab88
--- /dev/null
+++ b/【实践课外】5.循环结构2/7-1 求整数段和.c	
@@ -0,0 +1,25 @@
+#include <stdio.h>
+
+int main() {
+    int a, b, sum = 0;
+
+    scanf("%d %d", &a, &b);
+
+    for (int i = 0; i < (b - a + 1); i++) {
+        printf("%5d", a + i);
+
+        sum += a + i;
+
+        if (i % 5 == 4) {
+            printf("\n");
+        }
+    }
+
+    if ((b - a) % 5 != 4) {
+        printf("\n");
+    }
+
+    printf("Sum = %d\n", sum);
+
+    return 0;
+}
diff --git a/【实践课外】5.循环结构2/7-1 求整数段和.jpg b/【实践课外】5.循环结构2/7-1 求整数段和.jpg
new file mode 100644
index 0000000..eb46bba
Binary files /dev/null and b/【实践课外】5.循环结构2/7-1 求整数段和.jpg differ
diff --git a/【实践课外】5.循环结构2/7-2 循环-aaaa.c b/【实践课外】5.循环结构2/7-2 循环-aaaa.c
new file mode 100644
index 0000000..c07de2a
--- /dev/null
+++ b/【实践课外】5.循环结构2/7-2 循环-aaaa.c	
@@ -0,0 +1,21 @@
+#include <stdio.h>
+
+int main() {
+    int a, n, sum = 0;
+
+    scanf("%d%d", &a, &n);
+
+    for (int i = 1; i <= n; i++) {
+        int x = 0;
+
+        for (int j = 0; j < i; j++) {
+            x = x * 10 + a;
+        }
+
+        sum += x;
+    }
+
+    printf("%d\n", sum);
+
+    return 0;
+}
diff --git a/【实践课外】5.循环结构2/7-2 循环-aaaa.jpg b/【实践课外】5.循环结构2/7-2 循环-aaaa.jpg
new file mode 100644
index 0000000..659a45a
Binary files /dev/null and b/【实践课外】5.循环结构2/7-2 循环-aaaa.jpg differ
diff --git a/【实践课外】5.循环结构2/7-3 循环-完数.c b/【实践课外】5.循环结构2/7-3 循环-完数.c
new file mode 100644
index 0000000..a38c98b
--- /dev/null
+++ b/【实践课外】5.循环结构2/7-3 循环-完数.c	
@@ -0,0 +1,21 @@
+#include <stdio.h>
+
+int main() {
+    int n, sum = 0;
+
+    scanf("%d", &n);
+
+    for (int i = 1; i < n; i++) {
+        if (n % i == 0) {
+            sum += i;
+        }
+    }
+
+    if (sum == n) {
+        printf("YES\n");
+    } else {
+        printf("NO\n");
+    }
+
+    return 0;
+}
diff --git a/【实践课外】5.循环结构2/7-3 循环-完数.jpg b/【实践课外】5.循环结构2/7-3 循环-完数.jpg
new file mode 100644
index 0000000..b8afe19
Binary files /dev/null and b/【实践课外】5.循环结构2/7-3 循环-完数.jpg differ
diff --git a/【实践课外】5.循环结构2/7-4 输出三角形字符阵列.c b/【实践课外】5.循环结构2/7-4 输出三角形字符阵列.c
new file mode 100644
index 0000000..2cce9c1
--- /dev/null
+++ b/【实践课外】5.循环结构2/7-4 输出三角形字符阵列.c	
@@ -0,0 +1,18 @@
+#include <stdio.h>
+
+int main() {
+    int n;
+    char c = 'A';
+
+    scanf("%d", &n);
+
+    for (int i = n; i >= 1; i--) {
+        for (int j = 1; j <= i; j++) {
+            printf("%c ", c++);
+        }
+
+        printf("\n");
+    }
+
+    return 0;
+}
diff --git a/【实践课外】5.循环结构2/7-4 输出三角形字符阵列.jpg b/【实践课外】5.循环结构2/7-4 输出三角形字符阵列.jpg
new file mode 100644
index 0000000..d630381
Binary files /dev/null and b/【实践课外】5.循环结构2/7-4 输出三角形字符阵列.jpg differ
diff --git a/【实践课外】5.循环结构2/7-5 打印九九口诀表.c b/【实践课外】5.循环结构2/7-5 打印九九口诀表.c
new file mode 100644
index 0000000..52e07df
--- /dev/null
+++ b/【实践课外】5.循环结构2/7-5 打印九九口诀表.c	
@@ -0,0 +1,17 @@
+#include <stdio.h>
+
+int main() {
+    int n;
+
+    scanf("%d", &n);
+
+    for (int i = 1; i <= n; i++) {
+        for (int j = 1; j <= i; j++) {
+            printf("%d*%d=%-4d", j, i, i * j);
+        }
+
+        printf("\n");
+    }
+
+    return 0;
+}
diff --git a/【实践课外】5.循环结构2/7-5 打印九九口诀表.jpg b/【实践课外】5.循环结构2/7-5 打印九九口诀表.jpg
new file mode 100644
index 0000000..b873166
Binary files /dev/null and b/【实践课外】5.循环结构2/7-5 打印九九口诀表.jpg differ
diff --git a/【实践课外】5.循环结构2/7-6 换硬币.c b/【实践课外】5.循环结构2/7-6 换硬币.c
new file mode 100644
index 0000000..a2954ab
--- /dev/null
+++ b/【实践课外】5.循环结构2/7-6 换硬币.c	
@@ -0,0 +1,23 @@
+#include <stdio.h>
+
+int main() {
+    int x, count = 0;
+
+    scanf("%d", &x);
+
+    for (int i = x / 5; i >= 1; i--) {
+        for (int j = x / 2; j >= 1; j--) {
+            for (int k = x; k >= 1; k--) {
+                if (i * 5 + j * 2 + k == x) {
+                    printf("fen5:%d, fen2:%d, fen1:%d, total:%d\n", i, j, k, i + j + k);
+
+                    count++;
+                }
+            }
+        }
+    }
+
+    printf("count = %d\n", count);
+
+    return 0;
+}
diff --git a/【实践课外】5.循环结构2/7-6 换硬币.jpg b/【实践课外】5.循环结构2/7-6 换硬币.jpg
new file mode 100644
index 0000000..66ce44a
Binary files /dev/null and b/【实践课外】5.循环结构2/7-6 换硬币.jpg differ
diff --git a/【实践课外】5.循环结构2/7-7 猜数字游戏.c b/【实践课外】5.循环结构2/7-7 猜数字游戏.c
new file mode 100644
index 0000000..3b0f414
--- /dev/null
+++ b/【实践课外】5.循环结构2/7-7 猜数字游戏.c	
@@ -0,0 +1,42 @@
+#include <stdio.h>
+
+int main() {
+    int num, n, finished = 0;
+
+    scanf("%d%d", &num, &n);
+
+    for (int i = 1; i <= n; i++) {
+        int x;
+
+        scanf("%d", &x);
+
+        if (x < 0) {
+            printf("Game Over\n");
+
+            finished = 1;
+            break;
+        } else if (x == num) {
+            if (i == 1) {
+                printf("Bingo!\n");
+            } else if (i <= 3) {
+                printf("Lucky You!\n");
+            } else {
+                printf("Good Guess!\n");
+            }
+
+            finished = 1;
+
+            break;
+        } else if (x < num) {
+            printf("Too small\n");
+        } else {  // x > num
+            printf("Too big\n");
+        }
+    }
+
+    if (finished == 0) {
+        printf("Game Over\n");
+    }
+
+    return 0;
+}
diff --git a/【实践课外】5.循环结构2/7-7 猜数字游戏.jpg b/【实践课外】5.循环结构2/7-7 猜数字游戏.jpg
new file mode 100644
index 0000000..aa73772
Binary files /dev/null and b/【实践课外】5.循环结构2/7-7 猜数字游戏.jpg differ
diff --git a/【实践课外】5.循环结构2/7-8 沙漏.c b/【实践课外】5.循环结构2/7-8 沙漏.c
new file mode 100644
index 0000000..951230d
--- /dev/null
+++ b/【实践课外】5.循环结构2/7-8 沙漏.c	
@@ -0,0 +1,39 @@
+#include <stdio.h>
+
+int main() {
+    int n;
+
+    scanf("%d", &n);
+
+    // 上半部分
+    for (int i = n * 2 - 1; i >= 1; i -= 2) {
+        // 空格
+        for (int j = 1; j <= (n * 2 - 1 - i) / 2; j++) {
+            printf(" ");
+        }
+
+        // 沙漏主体
+        for (int j = 1; j <= i; j++) {
+            printf("#");
+        }
+
+        printf("\n");
+    }
+
+    // 下半部分
+    for (int i = 3; i <= n * 2 - 1; i+= 2) {
+        // 空格
+        for (int j = 1; j <= (n * 2 - 1 - i) / 2; j++) {
+            printf(" ");
+        }
+
+        // 沙漏主体
+        for (int j = 1; j <= i; j++) {
+            printf("#");
+        }
+
+        printf("\n");
+    }
+
+    return 0;
+}
diff --git a/【实践课外】5.循环结构2/7-8 沙漏.jpg b/【实践课外】5.循环结构2/7-8 沙漏.jpg
new file mode 100644
index 0000000..2ba77aa
Binary files /dev/null and b/【实践课外】5.循环结构2/7-8 沙漏.jpg differ